DE3305418A1 - Casting device, in particular vacuum-pressure casting device, for dentistry - Google Patents

Abstract

The casting device, in particular vacuum-pressure casting device for dentistry, has a heatable (induction coil 31) pot (24) which is arranged continuously above a casting muffle (25). The pot (24) and the casting muffle (25) are mounted in sliding parts (12, 13) which can be moved separately relative to a supporting structure (10) and, in addition, can be displaced vertically by means of a piston-cylinder arrangement (32, 33) to seal a chamber (56) formed by a cross beam (34) and the two sliding parts (12, 13). At its bottom end, the pot (24) can be opened, this preferably being achieved by the pot (24) being divided in a vertical plane, it being possible to raise one part (24'') of the pot via a lifting mechanism (45, 45'; 46, 47), more specifically upon an upward movement of the casting muffle (25) towards the pot (24). <IMAGE>

Description

description

The invention relates to a casting device, in particular a vacuum pressure casting device for dental technology, with a heatable crucible, a casting muffle (casting flask) that can be connected to the crucible and a chamber that can be evacuated or pressurized with compressed gas, in which the crucible and the casting muffle are arranged.

Such a casting device is known from DE-OS 26 35 182 and DE-OS 29 21 192. Form crucible and casting muffle in this case an essentially closed unit during the heating and casting process. While heating up

-δι is the crucible below the casting muffle. Is the casting material heated to the casting temperature, the entire unit is rotated 150-180 ° so that the Melt runs out of the crucible into the muffle. In DE-OS 29 21 192 the crucible has at its the Muffle side facing a bead with centering ring, which are adapted to a pouring funnel of the muffle.

The disadvantage here is the rotational movement through 150 or 180 °, especially since the melt flows over the even cooler area the crucible is conveyed and thereby cooled. The surface wetting of the crucible wall also not always the melt "dumped out" completely.

In the casting device of DE-OS 26 35 182, the crucible and muffle are in a substantially can-shaped casting chamber housed, which is accessible and lockable from above. Before each casting process, the lid must be the Chamber opened, the material to be melted is poured into the crucible and then the muffle is placed on the crucible placed, centered and fastened there. The casting chamber must then be closed before the then the automatically running heating and pouring process can begin. These steps are time consuming and can only be carried out by trained personnel.

Finally, with this pouring device, the tilting speed during pouring is also of decisive importance, since turning too slowly will result in an incomplete casting can arise, while rotating too fast will result in spillage of the melt. Accordingly a complex control device is provided there, which ensures a predetermined tilting speed.

The present invention is intended to avoid these disadvantages.

The object of the invention is therefore to improve the casting device of the type mentioned in that at easy handling, perfect casting results can be achieved.

This object is achieved according to the invention in that the crucible is always arranged above the casting muffle and that the crucible is open at its lower end.

Tilting a unit consisting of a crucible and muffle is therefore no longer necessary. Since the melt on the runs out of the lower hot end of the crucible, there is also no risk of excessive cooling during the casting process. The crucible and muffle do not have to be exactly centered or relatively at their connection point be tightly connected, as the melt under the influence of gravity directly into the pouring funnel Muffle flows and, in the absence of the tilting movement, there is also no risk of it being laterally between the crucible and Muffle flows out.

For opening the crucible look at its lower end the invention presents several variants. According to a variant, the crucible is in a substantially vertical position Split level, the crucible parts being movable relative to one another. The crucible parts are preferably here parallel to the parting plane in the vertical direction to each other displaceable, it being particularly advantageous if one crucible part is stationary while the other Crucible part is displaceable.

According to another variant of the invention, in which the crucible also lies in a substantially vertical position Level is divided, the two crucible parts are opened by a pivoting movement. Here are the two

the crucible parts pivotable about a horizontal axis located in the upper area of the crucible parts. After a In the variant, the axis is parallel to the parting plane, see above that the crucible is opened and closed in a "pincer movement". Another variant is the Axis, on the other hand, is perpendicular to the parting plane, so that the two "half-shells" are pivoted against each other, that their abutting surfaces remain in the plane of division.

According to a further variant, which is particularly advantageous in the case of double-walled crucibles, the crucible instructs its lower end has a pouring opening which can be closed by a stopper. That plug is inside of the crucible and is raised to open.

In all variants, the crucible can taper conically downwards towards the casting muffle, whereby it preferably in the variant with the crucible parts that are vertically displaceable relative to one another, a circumferential collar has its outside, which can be brought to the stop with a retaining ring.

In the case of a divided crucible (all variants) it is useful to when one part of the crucible is stationary and only the other is movable.

According to an advantageous development of the invention are the crucible (all variants described above) and the casting muffle each in one opposite a frame structure slidable sliding part held, the two sliding parts together with the frame structure the evacuable or Form pressurized chamber with pressurized gas. Both push parts can be pulled out of or pushed into the framework similar to a drawer will. This makes it easy to fill the

-11 crucible or replacement of the casting muffle possible.

So that the sliding parts together with the framework form a gas-tight chamber and still move easily can be, is according to a development of the invention provided that both thrust parts are vertically displaceable with respect to the structure and that they are attached to the neighboring one Joint surfaces between the two sliding parts or one or both sliding parts and the framework Have seals. If both push parts are pushed in, they are preferably lifted by a lifting device a piston-cylinder arrangement on one of the two Pushing parts acts, pressed against the structure, in which case, in cooperation with the mentioned seals, the gas-tight evacuable or pressurized with pressurized gas chamber is closed.

Preferably, the lower thrust part receiving the casting muffle has a U-shaped cross-sectional profile, which the Crucible receiving upper thrust part has a substantially H-shaped cross-sectional profile and an upper crossbar of the framework has a U-shaped cross-sectional profile facing the upper thrust part. The seals are in place then between the upper and the lower sliding part and between the upper sliding part and the upper crossbar. The two sliding parts and the upper cross bar then form the one which can be evacuated or can be pressurized with pressurized gas Chamber.

in this case the piston-cylinder arrangement acts preferentially on the lower thrust part and then on the upper thrust part, with both thrust parts against the upper crossbar must be pressed. The lifting device is supported on a lower crossbar of the structure.

In addition to the vertical movement of the push parts to the According to a further embodiment of the invention, the crucible and the casting muffle close to one another can be moved in the vertical direction. During the heating process, the crucible and muffle can be (relatively far) apart be removed, which is particularly advantageous when heating by means of an induction coil, as it does this the risk of a sparkover is reduced. In a structurally simple solution here is the Casting muffle can be moved while the crucible is stationary (apart from the crucible part that can be opened).

A particularly favorable arrangement for this provides that a second, supported opposite the lower thrust part Lifting device, preferably a piston-cylinder arrangement the casting muffle moves vertically. This second lifting device can preferably be in a recess (chamber) be arranged of the lower thrust part.

It is particularly favorable when the muffle is raised in the direction of the crucible at the same time for opening the Crucible. For this purpose, a lifting rod is provided which, on the one hand, is connected to the second lifting device (for lifting the muffle) and on the other hand with the opening mechanism for the crucible, d. H. either the movable crucible part or the plug is connected.

To prevent the crucible from opening too early, see a further development of the invention that the lifting linkage has a dead gear, so that the crucible only briefly before reaching the upper end position of the casting muffle is opened.

Such a dead gear is realized in a particularly simple manner in that the lifting linkage has two aligned plungers

has, d. H. is thus divided, with the mutually facing ends of this plunger when the casting muffle is lowered are at a distance from each other. Only touch when the muffle is just before its upper end position these two plungers, which then initiates the opening of the crucible.

The arrangement with the push parts enables a favorable development of the invention, according to which all Parts of the heating device for the crucible are arranged in the upper push part and can be moved with this. In particular in the case of high-frequency induction heating, the high-frequency generator and the supply lines are in fixed relation to each other, which has the advantage that no high-frequency currents carry Lines of variable length are required. The high-frequency circuit cannot be detuned with it, and there is also no risk of arcing between high-frequency lines that may have been chafed through.

According to a further development of the invention, the push parts are mounted on guide rails opposite the frame structure, preferably via ball bearings provided with play in the vertical direction.

In the case of the crucible consisting of two crucible parts, according to a further development of the invention, it is sufficient if when the crucible is closed, their opposing interfaces directly touch each other. Additional Seals are not required because of the surface tension of the materials that are usually melted prevents the melt from escaping through the slight gap between the crucible parts. Preferably the Rotationally symmetrical crucible for all variants, covered on its vertical axis.

Appropriately, both thrust parts are provided with coolant lines through which a cooling medium such as. B. Water can be directed.

The framework and in particular the upper crossbar has at least one closable opening for connection a vacuum pump or a pressurized gas source, this opening being in communication with the chamber.

The crucibles are made for cobalt-chrome alloys as well Nickel-chromium alloys made from ceramics. Carbon or graphite crucibles are required for processing gold. In the latter case, double-walled crucibles are also used, with the outer crucible made of ceramic and the

] _5 insert crucible is made of graphite. For graphite crucibles is the variant described above with the outflow opening cheaper, in which case the plug is made of ceramic, quartz or the like.

In the following, the invention is based on exemplary embodiments in connection with the drawing explained. It shows:

Fig. 1 is a perspective schematic diagram of the Pouring device of the invention;

Fig. 2 is a vertical section of the casting device in the operating state according to a first embodiment the invention;

3 shows a schematic side view of a crucible

according to a variant of the invention;

Figure 4 is a sectional view of one half of the crucible of Figure 3;

FIG. 5 is a plan view of the crucible half of FIG. 4; and

6 shows a sectional view similar to FIG. 2 of a further exemplary embodiment of the invention.

The casting device of Fig. 1 is housed in a larger container or box-like cabinet 14, which is in Fig. 1 is shown only in rough contours. In this cabinet 14 there is a frame structure 10 for receiving of two push parts 12 and 13. The push part 12 receives a crucible 24 and the push part 13 a casting muffle 25. Both push parts 12 and 13 are on precise guide rails 21 and 28 respectively opposite the framework

! 5 10 movable, d. H. they can be similar to drawers be moved horizontally.

On the back, d. H. A high-frequency generator 11 is arranged in the part of the sliding part 12 located in the cabinet, the high-frequency energy for an induction heating coil, not shown in FIG. 1, for the crucible 24 supplies. The high frequency generator 11 includes a Resonant circuit coil 15, a grid coil 16 and resonant circuit capacitors 20, which have a metallic connector 30 are electrically connected. The coils 15 and 16 and the capacitors 20 are on a vertical Holding plate 17 attached, which in turn is held on a spacer plate 19 via an insulating intermediate piece 18 which is connected to the actual thrust part 12. Thus, the entire high-frequency generator move together with the push part 12. Only a power cord 11 'for the energy supply of the high-frequency generator 11 must therefore be designed so that it lengthen or shorten when the thrust part 12 is moved can.

The resonant circuit coil 15 here consists of a copper pipe through which coolant can be passed. This Copper pipe opens in one piece into a supply line 22 which conducts the high-frequency energy to the induction coil. A return line, 23 leads from the induction coil to the resonant circuit capacitors 20. Around the upper openings for the crucible 24 and the casting muffle 25 sealing rings 35 and 36 are arranged, which in connection with Fig. 2 will be explained in more detail. Both push parts 12, 13 are provided with handles on the front side, which allow easy operation.

It can be seen that each push part is extended individually can be, whereby a simple loading of the crucible 24 or an easy replacement of the casting muffle 25 is possible. Finally, the support frame 10 has a sight glass 48 on its upper side, which when the Push part 12 is exactly above crucible 24 and allows observation of the melt.

FIG. 2 shows a vertical section through the casting device of FIG. 1 with the sliding parts 12, 13 closed. Same Reference numerals as in Fig. 1 denote the same parts.

The frame structure 10 is essentially box-shaped, on its front side for retraction and extension the push parts 12 and 13, however, open. The upper part of the framework 10 has a reinforced crossbar 34, which has a downwardly directed U-shaped profile. The horizontal abutment surfaces of this profile lie the top of the upper thrust part 12 opposite, which has a substantially H-shaped cross-sectional profile. In the crossbar of this H-shaped profile, a recess is provided into which the crucible 24 can be inserted.

Around the lower half of the crucible 24 is the

Induction coil 31 arranged at a certain distance from the crucible 24 and ensures in connection with the high-frequency generator 11 in FIG. 1 for heating the material to be melted in the crucible 24. The crucible 24 extends from above conically tapering towards the bottom and has a circumferential shoulder or shoulder in the area of its upper end Bund 49 (Fig. 3), which comes to rest on a retaining ring 44. The retaining ring 44 is on the top of the crossbar of the H-shaped cross-sectional profile. The upper push part 12 is in lateral guide rails 21 displaceable with respect to the structure 10. The storage takes place via ball bearings 29, these ball bearings having a game have, which allows a vertical displacement of the thrust part 12. The game here is so big that the push part 12 can be moved so far in the direction of the upper crossbar 34 that the associated Abutment surfaces of the thrust part 12 and the cross bar 34 can be brought into firm contact with one another, the in a groove on the top of the thrust part 12 provided seal 35 for a loadable with overpressure or underpressure tight seal between the upper cross bar 34 and the upper sliding part 12 ensures. In the wall of the sliding part 12, one or more coolant lines 38 can be provided through which coolant, for example water is directed.

In the embodiment of FIG. 2, the crucible 24 is divided in a vertical, central plane 26 so that two mirror-symmetrical crucible parts 24 'and 24 "are opposite one another. Butt surfaces of the two crucible parts 24 'and 24 "are in direct contact with one another, i.e. without an additional seal. Due to the conical shape of the crucible 24 and the retaining ring 44, the crucible parts 24 'and 24 "are held by their own weight of the crucible 24 and the weight of the material to be melted

pressed together sufficiently to prevent the Prevent melt. Of course, this is also due to the relatively high surface tension of the enamel materials used at.

The two crucible parts 24 'and 24 "are relative to one another displaceable, wherein in the embodiment of FIG one crucible part 24 ′ is stationary, while the other crucible part 24 ″ is vertically displaceable parallel to the dividing plane 26 is. This is shown in dashed lines

Is the crucible part 24 'shown in dashed lines In the raised position, the crucible 24 is open and the melt can flow down into the casting muffle 25. Due to the conical shape of the crucible 24, a favorable shape of the pouring opening is also created here, which ensures an even flow of the melt.

Below the push part 12, the lower push part 13 is arranged, which is also in ball-bearing guide rails 28 is displaceable. Here, too, the ball bearing 29 has a game that allows vertical displacement of the thrust part 13 allowed. The push part 13 has a substantially U-shaped cross-sectional profile, which in its interior the inclusion of the casting muffle 25 allows. The top of the thrust part 13 forms an abutment surface with the underside of the upper thrust part 12 can be brought into contact. Here, too, is in a groove on the abutment surface of the lower thrust part 13, a seal 36 let in.

The lower thrust part 13 is through a piston-cylinder arrangement (Cylinder 32 and piston 33), which are supported on a lower cross bar 58 on the underside of the framework 10 can be moved vertically. If the lower thrust part 13 is raised by the piston-cylinder arrangement 32, 33, so it presses against the upper thrust part 12, whereby

this is also raised until it reaches the upper (Juerriegel comes to a stop. The upper cross bar 34, the upper sliding part 12 and the lower sliding part 13 form together with the seals 35 and 36, a chamber 56 which can be evacuated or pressurized with compressed gas. These Chamber 56 thus receives the crucible 24 and the casting muffle 25 and thus forms a melting and casting space. in the Upper cross bar openings 37 and 57 are provided, through which the chamber 56 with a vacuum pump or a Pressurized gas source is connectable.

In addition to that from the piston-cylinder arrangement 32, 33 formed lifting device, which is used to close the casting device, is a further, piston-cylinder arrangement 39, 40 formed lifting device is provided, which for raising and lowering the casting muffle 25 and for the simultaneous open or close the crucible 24 is used. The piston-cylinder arrangement 39, 40 is arranged in a recess 41 in the lower region of the thrust part 13. The piston rod 39 protrudes through the bottom wall of the thrust part 13 and is attached to a support plate 47, which the casting muffle 25 carries. The casting muffle 25 is thus displaceable between two limit positions, the upper, The limit position shown in dashed lines is used for the casting process. This is where the funnel comes in the casting muffle 25 to lie just below the pouring opening of the crucible 24.

The support plate 47 is extended to one side (right in Fig. 2) to a connecting arm on which a vertical Lifting ram 46 is attached. By lifting the casting muffle, the lifting ram 46 is also raised. This lift tappet 46 is aligned when the push parts are closed with a further lifting tappet 45 ', which is located in an opening in the transverse part of the H-shaped cross-sectional profile of the thrust part 12 is guided and opens into a horizontal lifting arm 45 which

33Ό5418

is fixed in a bore 50 (Fig. 3) of the displaceable crucible part 24 ". The mutually facing ends of the two Lifting tappets 45 'and 46 are at a distance in the lower limit position of the piston-cylinder arrangement 39, 40 to each other. This creates a "dead gear" which ensures that only shortly before the upper limit position is reached the casting muffle 25, the two lift tappets 45 'and 46 come into contact with one another and then in the case of the last one Part of the upward movement of the casting muffle 25 for opening of the crucible 24.

The operation of the pouring device is as follows:

Both piston-cylinder arrangements 32, 33 are in the idle state or 39, 40 in their lower position. Both push parts 12 and 13 can be pulled out separately and charged with melting material or a casting muffle 25. Are both Push parts 12, 13 are then closed, so the piston-cylinder arrangement 32, 33 locks the casting device so that the chamber 56 is tight. Depending on the melt material, the Chamber 56 evacuated or with protective gas such. B. filled with argon. The high frequency generator 11 is then switched on, whereby the material to be melted is heated via the induction coil 31. After a specified period of time or according to optical The casting process is then initiated by checking the melt via the sight glass 48. As a rule, the heating is used for this purpose switched off and by actuating the piston-cylinder arrangement 39, 40, the casting muffle 25 is moved vertically upwards. Shortly before the upper limit position is reached, the lift ram 46, 45 'and the lift arm 45 move the right one Crucible half 24 ″ shifted, with which the crucible 24 is opened and the melt run down into the casting muffle 25 can. The chamber 56 is then for a good casting result with compressed gas, for example protective gas such as argon or compressed air applied, as is generally known in casting technology.

During the entire process, the two push parts 12, 13 are cooled by coolant in the lines 38. To

"V ^y: 3305A18

Completion of the casting process and possibly cooling of the melt in the casting muffle 25 are the pressure in the chamber 56 drained and both piston-cylinder assemblies 39, 40 and 33, 32 brought to their rest position, whereupon the push parts 12, 13 can be pulled out, the casting muffle 25 removed and a new process initiated can be.

All of these processes can be monitored automatically by a control device not belonging to the invention.

For the opening of the divided crucible 24, the invention provides still further variants not shown in the drawing. According to a variant, the crucible 24 is similar unfolded like a pincer movement. For this purpose, the two crucible parts 24 'and 24 "are in the area of their upper ones Ends held in pivot bearings, which in Fig. 2 are perpendicular to the plane of the drawing. The lifting arm 45 is then articulated connected to the associated crucible part. If both parts of the crucible are to be swiveled, the plungers can also be used 45 'and 46 can be provided in duplicate with mirror symmetry to the plane 26. By lifting the casting muffle 25 can then Swiveling movement of the crucible parts are effected.

According to a further variant of the invention, the crucible can be opened in that one or both crucible parts be pivoted about an axis which runs through the lifting arm 45 of FIG. The plungers 45 'and 46 as well as a no The swivel arm shown (analogous to the lifting arm 45) are then offset from the plane of the drawing in FIG. 2 and thus with connected to the crucible part to be pivoted in each case, so that the desired pivoting movement occurs.

With the variants just described for opening the crucible 24, the retaining ring 44 can either be omitted entirely

because the pivot axes are firmly held on the thrust part 12. Instead of the retaining ring 44 can also be a elastic element can be provided which applies the force required to close the crucible 24.

FIGS. 3 through 5 show that used in FIG. 2 in greater detail Crucible 24. The crucible 24 here is a rotationally symmetrical body which is located in the vertical center plane 26 is divided. In its lower area 53 the crucible tapers conically downwards, this conical area opens into a termination area 59 which is at an obtuse angle to the area 53. The top of the conical Area opens into a collar 49 running around the outer circumference of the crucible 24, which acts as a stop shoulder for the retaining ring 44 is used. In the illustrated embodiment is the area adjoining the collar 49 upwards towards the top, i. H. towards the filling opening of the crucible 24 again slightly tapered to a point. In this area a bore 50 is provided which receives the lifting arm 45.

Fig. 6 shows a further variant of the casting device, which differs from the casting device of FIG. 2 essentially only the type of opening and closing of the crucible 24 differs. The same reference numerals as in FIG. 2 denote here too the same parts. Instead of a divided crucible 24, a crucible 24 with a drain opening designed as a bore is used here 51 used. This drainage opening 51 can be closed by a plug 52, the plug 52 over the lifting arm 45 can be raised and lowered. In Fig. 6, the crucible 24 is double-walled and consists of one outer crucible 55 and an insert crucible 54. The insert crucible 54 can be made of graphite, for example, while the outer crucible 55 is made of ceramic. Both crucibles 54,55 then have a drain opening at their lower end, wherein the drain opening of the closed by the plug 52 Insert crucible 54 has a slightly smaller diameter than that

-23-drain opening 51 of the outer crucible 55.

The remaining parts of the casting device of FIG. 6 correspond to those of FIG. 2, so that they will not be discussed in more detail here must become.

By actuating the piston-cylinder arrangement 39, 40 is the casting muffle 25 is raised and at the same time the lifting ram 46, which is then shortly before reaching the upper limit position the casting muffle 25 raises the lifting arm 45, whereby the plug 52 is raised and the drain opening 51 is released. the Melt then runs through the discharge opening 51 into the casting muffle 25. All other processes correspond to those of FIG.

Finally, it should be emphasized that the structure is highly resilient, so that the chamber 56 high and high Endures oppression. For a flawless casting result in which the melt is printed in all mold cavities of the muffle it has proven to be beneficial if an overpressure of 2 to 3 bar is used. This has the The advantage is that you can work with a colder melt, but still produce very precise moldings turn around .

For processing melt materials made from cobalt-chromium alloys As well as nickel-chromium alloys, the crucible 24 consists of ceramic material. For processing of gold, carbon crucibles or graphite crucibles are useful, which then form the insert crucibles 54 of FIG outer crucible 55 continue to consist of ceramic material can. The plug 52 can be made of ceramic material, quartz or the like.

Of course, the sight glass 48 is gas-tight in the upper part

Cross bar 34 is attached, which is only indicated schematically by a retaining and sealing ring 42.

During the melting process, a negative pressure is preferably used in the chamber 56, which is the case here induction coil 31 used is about 150 mbar. A A lower residual gas pressure is not recommended to avoid arcing on the induction coil 31. In order to avoid oxidation problems that still occur with noble metals at this residual gas pressure, the above is used Graphite crucible used, which prevents oxidation through combustion.

Alternatively, instead of the negative pressure, an inert gas For example, argon can be used, which at higher gas pressure also causes arcing of the induction coil avoids. This inert gas can be introduced via the opening 57.

All technical details presented in the patent claims, the description and the drawing can be essential to the invention both individually and in any combination.

Meissner & Bolte patent attorneys

Applicant:

BEGO Bremer Goldschlägerei WiIh. Herbst GmbH & Co. Emil-Sommer-Strasse 7-9

2800 Bremen 41

Bremen, February 16, 1983

9118

Reference symbols

10 Framework 42 Retaining / sealing ring 11th High frequency generator 43 12th Push part 1 44 Retaining ring 13th Push part 45 Lift arm 14th cabinet 46 Lift tappet 15th Resonant circuit coil 47 Support plate 16 Lattice coil 48 Sight glass 17th Retaining plate 49 Federation 18th Intermediate piece 50 drilling 19th Spacer plate 51 Drain opening 20th Condenser 52 plug 21 Guide rail 53 Crucible area / uni 22nd Supply line 54 Insert crucible 23 Return line 55 outer crucible 24 crucible 56 chamber 25th Casting muffle 57 opening 26th Partition level 58 Cross bar (lower) 27 Feed hopper 59 Closing area 28 Guide rail 29 ball-bearing 30th Connector 31 Induction coil 32 ZyI Indian 33 Pistons 34 Crossbar 35 Sealing ring 36 Sealing ring 37 opening 38 Coolant line 39 Piston rod 40 ZyI Indian 41 Recess

Claims (1)

Claims 1 .1 casting device, in particular vacuum pressure casting device for dental technology, with a heatable crucible, a casting muffle (casting flask) that can be connected to the crucible and a chamber that can be evacuated or pressurized with pressurized gas, in which the crucible and the casting muffle are arranged, thereby characterized in that the crucible (24) is always arranged above the casting muffle (25) and that the crucible is open at its lower end. 2. Casting device according to claim 1, characterized in that the crucible (24) in a substantially vertically lying plane (26) is divided, wherein the crucible parts (24 ', 24 ") are movable relative to one another. ■ 3. Casting device according to claim 2, characterized in that the crucible parts (24 ¹ , 24 ") parallel to the dividing plane (26) are displaceable relative to one another in the vertical direction. 4. Casting device according to claim 2 or 3, characterized in that the one crucible part (24 ¹ ) is stationary and the other crucible part (24 ") is displaceable. 5. Casting device according to one or more of claims 2 to 4, characterized in that the crucible (24) is tapered downwards towards the casting muffle (25) and has a circumferential collar (49) on its Has the outside which can be brought to a stop with a retaining ring (44). 6. Casting device according to one or more of claims 1 to 5, characterized in that the crucible (24) or the casting muffle (25) each in a sliding part (12 or 13) are held, the two push parts (12, 13) together with the framework (10) form the chamber (56) which can be evacuated or can be pressurized with pressurized gas. 7. Casting device according to claim 6, characterized in that the two push parts (12, 13) in addition are vertically displaceable with respect to the structure (10) and that on the adjacent abutment surfaces between the two Push parts (12, 13) or the push part and the frame structure (10) seals (36 and 35) are provided. 35 8. Casting device according to claim 6 or 7, characterized in that the casting muffle (25) receiving lower push part (13) has a U-shaped cross-sectional profile that the crucible (24) receiving upper push part (12) has a substantially H-shaped cross-sectional profile and that an upper crossbar (34) of the Framework ^ (10) one facing the upper thrust part (12) Has a U-shaped cross-sectional profile, the two sliding parts (12, 13) and the crossbar (34) form the chamber (56) which can be evacuated or pressurized with pressurized gas. 9. Casting device according to one or more of claims 6 to 9, characterized by a lifting device, preferably a piston-cylinder arrangement (33, 32), by means of which the lower thrust part (13) and thus also the upper thrust part (12) opposite a lower crossbar (58) of the framework (10) in the direction of the upper Cross bars (34) can be raised. 10. Casting device according to one or more of claims 1 to 9, characterized in that (additionally) the crucible (24) and the casting muffle (25) · are displaceable relative to one another in the vertical direction. 11. Casting device according to claim 10, characterized in that the casting muffle (25) opposite the stationary Crucible (24) is displaceable. 12. Casting device according to claim 10 or 11, characterized by a second, opposite to the lower thrust part (13) supported lifting device, preferably a piston-cylinder arrangement (39, 40), for vertical displacement the casting muffle (25). 19. Casting device according to one or more of the claims 6 to 17, characterized in that the sliding parts (12, 13) opposite the frame structure (10) are mounted on guide rails (21, 28). 20. Casting device according to claim 19, characterized in that the push parts (12, 13) over in vertical Direction provided with play ball bearings (29) are mounted on the guide rails (21, 28). 21. Casting device according to one or more of claims 2 to 20, characterized in that the crucible parts (24 ¹ , 24 ") are in direct contact with their opposing boundary surfaces, ie without an intermediate seal. 22. Casting device according to one or more of claims 1 to 21, characterized in that the Crucible (24) is rotationally symmetrical with respect to a vertical axis. 23. Casting device according to one or more of claims 1.5-22, characterized in that the Crucible (24) at its lower end has a drain opening (51) which can be closed by a movable plug (52) arranged in the interior of the crucible (24). 24. Casting device according to claim 23 in conjunction with one or more of claims 15 to 17, characterized characterized in that the plug (52) is connected to the lifting rod (45, 46, 47). 25. Casting device according to one or more of claims 1, 2, 4, 6-22, characterized in that one or both crucible parts (24 ¹ , 24 ") around a horizontal, -4- 13. Casting device according to claim 12, characterized in that the second lifting device (39, 40) in a recess (chamber) (41) of the lower thrust part (13) is arranged. 14. Casting device according to one or more of claims 10 to 13, characterized in that the The crucible (24) is opened when the casting muffle (25) is raised. 15. Casting device according to claim 14, characterized by a lifting rod (47, 46, 45), which on the one hand with the second lifting device (39, 40) and on the other hand with the movable crucible part (24 ") or an opening and Closing device for the crucible (24) is connected. 16. Casting device according to claim 15, characterized in that that the lifting rod (47, 46, 45) has a dead gear, so that the crucible (24) only shortly before Reaching the upper end position of the casting muffle (25) is opened. 17. Casting device according to claim 16, characterized in that the lifting rod (47, 46, 45) has two aligned plungers (4 ^ß , 45 ') whose ends facing each other are spaced apart when the casting muffle (25) is lowered. 18. Casting device according to one or more of the Proverbs 6 to 17, characterized in that all parts a heating device (31, 11, 15-18, 20, 22, 23) for the crucible (24) is arranged in the upper pusher part (12) and can be moved with it. are pivotable axis lying in the upper area of the crucible parts. 26. Casting device according to claim 25, characterized in that the axis is parallel to the parting plane (26) lies. 27. Casting device according to claim 25, characterized in that the axis is perpendicular to the parting plane (26) lies. 28. Casting device according to one or more of claims 25 to 27, characterized in that a rocker arm is connected on the one hand to a crucible part and on the other hand to the lifting rod (45, 46, 47). 29. Casting device according to one or more of claims 6 to 28, characterized in that the push parts (12, 13) have coolant lines (38). 30. Casting device according to one or more of claims 6 to 29, characterized in that the frame structure (10) and in particular the upper cross bar (34) at least one closable opening (37, 57) for connection to a vacuum pump or a compressed gas source, which is in communication with the chamber (56). 31. Casting device according to claim 23 or 24, characterized in that the crucible (24) consists of two nested Crucible parts (54, 55), the outer crucible (55) made of ceramic and the inner crucible (insert crucible) (54) consists of graphite and wherein the crucible parts have flush outflow openings (51). 32. Casting device according to claim 23, characterized in that the plug (52) made of ceramic, quartz or the like. is. Meissner & Bolte patent attorneys